How do you memorialize something no one can forge the new 9/11 museum faced a seemingly impossible task turning an inside look at national tragedy into a fitting tribute. Here is ABC's David Muir. Reporter: As we walk down into the museum, the time there on the wall, 8:30 A.M., it was still a beautiful morning. Then everything changed. On the day of September 11th -- September 11th -- for frz. September 11th -- Americans remembering where they were, their own word lighting the way. We were actually in a meeting when some one barged in and said "Oh, my god a plane has crashed." On one of the first walls, the map, shows the flights when they turned and hijackers take control. As you walk through the museum beside us right there the survivor stairs. Literally hundreds of people used this staircase is an escape route on 9/11 when the attacks were taking place. Running down the stairs to safety was a life line. Reporter: The stairs weighed 58 tons. The entire museum built around them. Around the corner big red, the firetruck, ladder 3. So many remember that brave captain, patty brown. I'm on the 35th floor. Just relay to command post. We're trying to get out. Captain brown and ten of his men lost. Here in the museum they remember all the planes. These are parts from flight 77, pulled from the Pentagon. This clock frozen at 9:37. A melted rolodex. And some one's phone. In one of the rooms we discover a watch. Found in the field in shanksville, Pennsylvania, Todd beamers, one of the heroes who took back the flight. Right on his watch the date, the 11th. There was Florence Jones too who barely escaped the south tower. She told me she took off her shoes to get out faster and for years she kept them beneath her bed. They still have debris on them. On the bottom. When you flip them over there is debris from the floor. Reporter: Now Florence has given the shoes to the museum. And we found a message of hope. Even from that awful day. A nasa commander who saw the smoke and listened to what he said. Your city still looks difficult for everybody in there right now. Our thanks to David Muir for the look at the new museum. A day none of us will ever forget. Join us tomorrow for the dedication. ABC news will carry it live at 10:10 A.M.

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